Carnegie Mellon University engineering professor Costa Samaras, who studies electric vehicles, called the possibility that Tesla could shake up the trucking business “exciting,” but noted the firm’s challenges with getting vehicles to customers. “If it stays a concept car until 2030, then we have a problem,” Samaras said.Trucking produces a quarter of U.S. transportation-related greenhouse gas emissions, Samaras said. “If we can take that quarter and cut it in half with an all-electric fleet, that’s big news,” Samaras said.Two corporate giants quickly gave Tesla votes of confidence, with trucking behemoth J.B. Hunt pre-ordering “multiple” semis and retail titan Wal-Mart preordering 15 — five for the U.S. and 10 for Canada.More>>